W126 Expansion Valve - PeachParts Mercedes-Benz Forum

300SD81 · #1 04-06-2007, 10:30 AM

How in the world am I supposed to get to this thing? I can manage to fit a wrench on the bottom part, but the top is impossible... Where do they sell a crowfoot wrench up to 22mm? I can only even find a regular flarenut wrench up to 21mm...

Hit Man X · #2 04-06-2007, 11:00 AM

Adjustable crescent? Channel locks? I got mine out with a nice assortment of tools.

tangofox007 · #3 04-06-2007, 11:38 AM

Not sure about your model, but on some models the a/c fittings are SAE, not metric.

300SD81 · #4 04-06-2007, 12:09 PM

After an hour of struggling, and possibly having a bad back for the rest of my life, I now have 3 fittings disconnected and glow in the dark hands... That last 22mm connection at the top is near impossible to get off...

300SD81 · #5 04-06-2007, 12:25 PM

Just went and bought a 22mm crowfoot, and its too small! wtf?

tjohn · #6 04-06-2007, 12:36 PM

Quote:

Originally Posted by 300SD81

Just went and bought a 22mm crowfoot, and its too small! wtf?

Yeah, one's 24 mm, one's 22 , sorry. The expansion valve is one of the biggest PIA jobs I've done on this car. Not the most difficult, just PIA. I spent a couple hours on my head trying to thread those fittings back on. Just don't get frustrated and cross thread them.

300SD81 · #7 04-06-2007, 12:39 PM

Quote:

Originally Posted by tjohn

Yeah, one's 24 mm, one's 22 , sorry. The expansion valve is one of the biggest PIA jobs I've done on this car. Not the most difficult, just PIA. I spent a couple hours on my head trying to thread those fittings back on. Just don't get frustrated and cross thread them.

I'm pretty sure its 19 and 22, the 22 i bought was just like .001mm too small to fit... I matched it to a 7/8in of the same brand, and guess what... EXACT same size.. Returned it..

300SD81 · #8 04-06-2007, 01:22 PM

Whoever designed that location for the expansion valve is evil... But I finally got it out after digging up a set of needle nose channel lock pliers... With the way my hands and face are glowing in the dark right now though... I'll be surprised if I don't have cancer by this afternoon

dannym · #9 04-06-2007, 02:27 PM

I found that if you move the seat up you can rest your right shoulder on the seat and still reach the valve in relative comfort.
I don't remember having so much trouble. I bought a cheepo set of flare wrenches from a flea market and they fit nicely.
Yeah I know but that was over a year ago and I have never used them since.

Also get your odometer fixed. There's a tutorial at Diesel Giants website or if you need gears go to www.odometergears.com

Danny

300SD81 · #10 04-06-2007, 03:22 PM

My odometers different from the one on dg, but I know how to fix it.. Just don't feel like spending $40 on some little plastic gears..

Just flushed out my system with almost a gallon of methanol... Old compressor was good, so only thing in there was some nasty glow in the dark oil...

Robert Squires · #11 08-21-2008, 01:20 AM

* The selection of wrenches, crow's feet, etc is a hassle but what about the tubular frame runner that runs right across the front, 1/2" away, of the expansion valve? On at least the later W126's ('91 350SDL in this case), the factory added a tubular bird-cage in the center of the dash as a stiffener. It extends to the left over to the steering column, and virtually blocks access to the upper 2 exp valve fittings.
* Removing that tubular frame would amount to removing the dash. There ought to be another way.

Hit Man X · #12 08-21-2008, 01:22 AM

Quote:

Originally Posted by Robert Squires

* The selection of wrenches, crow's feet, etc is a hassle but what about the tubular frame runner that runs right across the front, 1/2" away, of the expansion valve? On at least the later W126's ('91 350SDL in this case), the factory added a tubular bird-cage in the center of the dash as a stiffener. It extends to the left over to the steering column, and virtually blocks access to the upper 2 exp valve fittings.
* Removing that tubular frame would amount to removing the dash. There ought to be another way.

Stubby wrenches help too, but that body stiffener deal has to come out/moved for access. I spent hours dicking with it in my 300sel a few weeks back.

Robert Squires · #13 08-21-2008, 09:43 PM

* Hit Man X, thanks for the help. The new expansion valve is installed and I thought I'd relate some additional information for anyone else who might be researching this job.
* That tubular frame, that I thought stretched all the way across to the glovebox, doesn't. It's only on the left side. Five bolts hold it in place. It appears to be a support strut for the steering column (spanning the distance from the steering column over to anchor on the left side of the transmission hump). Take the bolts out and move the frame a little. No need to remove it altogether to gain access to the exp valve. Of course, it requires removing the left carpeted panel covering the transmission hump first.
* This job is tough on the back. I recommend putting the car up on jack stands.

Classified · #14 08-29-2010, 02:26 AM

Quote:

Originally Posted by Robert Squires

* The selection of wrenches, crow's feet, etc is a hassle but what about the tubular frame runner that runs right across the front, 1/2" away, of the expansion valve? On at least the later W126's ('91 350SDL in this case), the factory added a tubular bird-cage in the center of the dash as a stiffener. It extends to the left over to the steering column, and virtually blocks access to the upper 2 exp valve fittings.
* Removing that tubular frame would amount to removing the dash. There ought to be another way.

I used a 22 crow foot and modified a 17 & 19 if anyone needs to borrow them I'd be willing to do so as long as I get them back. It took about 30 minutes once I tweaked the wrenches.

4thesporty · #15 08-29-2010, 12:19 PM

Just for clarification, those fittings are SAE, not metric. This is not to say that metric wrenches will not work, however when dealing with such a fragile connection (brass) in such an inconvenient place I would prefer to use the correct size to avoid any damage.